The giant pouched rats (genus Cricetomys) of sub-Saharan Africa are large muroid rodents. Their head and body lengths range from 25–45 cm (9–18 in) with scaly tails ranging from 36–46 cm (14–18 in). They weigh between 1.0 and 1.5 kg.

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Giant pouched rats are only distantly related to the true rats, though they were until recently placed in the family Muridae.[1] Recent molecular studies however, place them in the family Nesomyidae, part of an ancient radiation of African and Malagasymuroids. The name "pouched rat" refers to their large cheek pouches.

Females have been said to be capable of producing up to 10 litters yearly. Gestation is 27–36 days. One to five young are born at a time. Females have eight nipples.

The animals are nocturnal. They are omnivorous and feed on vegetation and small animals, especially insects. They have a particular taste for palm nuts. Like many related rodents that are hind gut fermenters, they are coprophagous, voiding soft fecal pellets of semi-digested food that they eat directly from the anus.

These rats are also becoming useful in some areas for detecting land mines, as their acute sense of smell is very effective in detecting explosives, and they are light enough to not detonate any of the mines.[2][3] The rats are being trained by APOPO, a nonprofit social venture based in Tanzania.

The procedure for training rats to detect land mines was conceived of and developed by Bart Weetjens from Belgium. Training starts at four weeks of age when the rats are handled to accustom them to humans and exposed to a variety of sights and sounds. They learn to associate a clicker with a food reward of banana or banana-peanut paste. They are then trained to indicate a hole with TNT in it by nosing it for five seconds. Then they learn to find the correct hole in a line of holes. Finally, the rat is trained to wear a harness and practises outdoors on a lead, finding inactivated mines under soil. At the end of their training, they are tested: they must find all the mines in an area of 400 square metres that has been seeded with inactivated mines. It is a blind test: their handlers do not know where the mines are. If they succeed, they are certified as bomb-sniffing rats.[4]

APOPO is also training the rats to detect tuberculosis by sniffing sputum samples; the rats can test many more samples than a scientist using more traditional methods—hundreds in a day vs. 30 to 40.[5] Land mine and tuberculosis sniffing rats are called HeroRATs.